1. Field of the Invention
The present invention relates to a paper guide device used upon feeding paper from its roll accommodated in a label printer, and more particularly, the present invention relates to a paper guide device which is modified in its construction to allow a pair of guide members for guiding feeding of paper at both widthwise edges of the paper to be adjusted in their positions in an easy manner, thereby rendering user convenience.
2. Description of the Related Art
Generally, a label printer is used to print a trade name, a price, an expiration date, etc. on a label sheet and thereby allow the printed label sheet to be affixed to a product. A number of label sheets are peelably attached to paper which is wound in the form of a roll, in a manner such that they are separated one from another by a certain distance. Depending upon a use, the paper has a, width of about 1 to 4 inches.
The paper which is wound in the form of a roll is accommodated in a body of the label printer. The paper roll is rotatably supported by a holding unit which extends through a center hole of the paper roll. Consequently, the paper can be continuously paid out from the roll as a printing work proceeds. The paper is fed between a printing roller and a printing head which constitute a printing section, by a feeding roller, to allow the label sheets to be properly printed.
Referring to FIG. 1, there is illustrated a label printer which employs a conventional paper guide device. The label printer designated by the reference numeral 10 has a printer body 3 and a cover 1 which is hingedly coupled to one end of the printer body 3. A printing head 2 is installed on a lower surface of a distal end of the cover 1. An accommodating section 4 for accommodating paper P wound in the form of a roll is defined in the printer body 3. The paper guide device for guiding both widthwise edges of the paper P is disposed in front of the accommodating section 4. Further, a printing roller 5 is arranged in front of the paper guide device to be brought into contact with the printing head 2. The printing roller 5 functions to support a label sheet attached to the paper, upon printing.
As shown in FIG. 2, the conventional paper guide device employed in the label printer 10 includes left and right guide members 6 and 7, a shaft element 8, and an adjustment knob 9. A pair of, slots 3a and 3b are defined through an upper wall of the printer body. 3 in a manner such that they extend in a widthwise direction of the printer body 3. The left and right guide members 6 and 7 are respectively defined, on one side surfaces facing each other, with guide grooves 6a and 7a in which both widthwise edges of the paper P are received and guided. The left and, right guide members 6 and 7 are further defined, adjacent to lower ends thereof, with threaded holes 6b and 7b, respectively. The shaft element 8 is rotatably supported by the printer body 3 directly below the pair of slots 3a and 3b. A right-hand threaded portion 8a and a left-hand threaded portion 8b are formed on a circumferential outer surface of the shaft element 8 in a manner such that they are separated from each other by a middle portion which is not threaded and they threadedly pass through the threaded holes 6b and 7b of the left and right guide members 6 and 7. The adjustment knob 9 is coupled to one end of the shaft element 8 and supported by a slide wall of the printer body 3, so that the shaft element 8 can be rotated upon manipulating the adjustment knob 9.
A pair of enlarged openings 3-1 and 3-2 are defined at inner ends of the pair of slots 3a and 3b, which inner ends neighbor to each other, in a manner such that substantially lower halves of the left and right guide members 6 and 7 are inserted through the pair of enlarged openings 3-1, and 3-2, respectively.
The middle portion of the shaft element 8, which middle portion is not threaded, passes through a support leg portion 3-3 which is integrally formed on an inner surface of the upper wall of the printer body 3, to be supported thereby. As can be readily seen from FIG. 2, the adjustment knob 9 passes through the side wall of the printer body 3 to be coupled to the one end of the shaft element 8.
It is to be readily understood that the threaded holes 6b and 7b of the left and right guide members 6 and 7 are right-hand threaded and left-hand threaded to be coupled with the right-hand threaded portion 8a and the left-hand threaded portion 8b of the shaft element 8, respectively.
Both widthwise edges of the paper P which is accommodated in the accommodating section 4 defined in the printer body 3 are guided as described below by the paper guide device constructed as mentioned above.
Referring to FIGS. 2 and 3, the lower halves of the left and right guide members 6 and 7 are respectively inserted through the pair of enlarged openings 3-1 and 3-2 defined at the inner ends of the pair of slots 3a and 3b which are defined through the printer body 3. The right-hand threaded portion 8a and the left-hand threaded portion 8b of the shaft element 8, which is rotatably supported by the printer body 3 directly below the pair of slots 3a and 3b, threadedly pass through the threaded holes 6b and 7b of the left and right guide members 6 and 7.
That is to say, since the right-hand threaded portion 8a and the left-hand threaded portion 8b of the shaft element 8 threadedly pass through the right-hand threaded hole 6b and the left-hand threaded hole 7b of the left and right guide members 6 and 7, respectively, if the shaft element 8 is rotated, the left and right guide members 6 and 7 can be moved along the pair of slots 3a and 3b in a horizontal direction in such a manner that a spacing measured between the left and right guide members 6 and 7 can be shortened or lengthened. The number of revolutions of the shaft element 8 corresponds to that of the adjustment knob 9 which is coupled to the one end of the shaft element 8 and supported by the side wall of the printer body 3.
As the case may be, it may be necessary to adjust a spacing between the left and right guide members 6 and 7 in conformity with a width of the paper P. Under this situation, by paying out the paper P from its roll rotatably supported by a center shaft (not shown) serving as a holding unit and by rotating in one direction the adjustment knob 9, that is, the shaft element 8, the widthwise edges of the paper P can be received and guided in the guide grooves 6a and 7a of the left and right guide members 6 and 7, and thereby, the paper P can be fed along a straight path to allow the label sheet to be properly printed.
When the paper, roll is to be changed with new one, the adjustment knob 9, which is positioned outward of and supported by the side wall of the printer body 3, is grasped and rotated in the other direction to free the widthwise edges of the paper P from the guide grooves 6a and 7a of the left and right guide members 6 and 7. At this time, the conventional paper guide device suffers from defects in that, since the adjustment knob 9 should be rotated in the other direction through at least 3 revolutions in order to appropriately and threadedly move the left and right guide members 6 and 7 on the right-hand threaded portion 8a and the left-hand threaded portion 8b of the shaft element 8 and rotated again in the reverse direction through at least 3 revolutions upon completion of paper roll changing in order to receive both widthwise edges of the paper P in the guide grooves 6a and 7a of the left and right guide members 6 and 7, user bothersomeness is caused and a paper roll changing time is extended.
Accordingly, the present invention has been made in an effort to solve the-problems occurring in the related art, and an object of the present invention is to provide a paper guide device used upon feeding paper from its roll accommodated in a label printer, which is modified in its construction to allow a pair of guide members for guiding feeding of the paper at both widthwise edges of the paper to be adjusted in their positions in an easy manner, thereby rendering user convenience.
In order to achieve the above object, according to the present invention, there is provided a paper guide device suitable for a label printer, comprising: left and right guide members defined, on one side surfaces thereof facing each other, with guide grooves which receive and guide both widthwise edges of paper, and formed, on respective rear and front surfaces thereof, with flat geared portions; left and right gear bands formed, on respective front and rear surfaces thereof, with rack gears which are respectively meshed with the flat geared portions of the left and right guide members; a pinion gear positioned between the left and right gear bands and meshed with the rack gears of them; and an adjustment knob slidably installed on a printer body and connected to one end of the right gear band.